Centrifuge discharge means



M y 1967 T. H. LITTLE ETAL 3,317,126

CENTRIFUGE DISCHARGE MEANS Filed Jan. 14, 1965 INVENTORS. THOMAS H. LITTLE LEONARD S APIRO BY ATTORNEY United States Patent O 3,317,126 CENTRIFUGE DISCHARGE MEANS Thomas H. Little, Devon, and Leonard Shapiro, Upper Darby, Pa., assignors to Pennsalt Chemicals Corporation, Philadelphia, Pa., a corporation of Pennsylvania Filed Jan. 14, 1965, Ser. No. 425,412 4 Claims. (Cl. 233-22) This invention relates to the centrifugal separation of a viscous component from a mixture of the component and a liquid. More specifically this invention relates to the discharging of a component from a centrifuge bowl in a manner which reduces the possibility of clogging of the centrifuge bowl and the discharge passages.

In the discharge of liquids from a centrifuge bowl 3. common expedient is to provide the bowl with an inwardly facing annular trough or pocket into which the liquid to be discharged is led by appropriate passages in the bowl structure. A skimmer or paring device is positioned to extend into the annular trough or pocket and to scoop up the liquid as it races by. One of the advantages of the skimming or paring device is that the liquid is discharged from the centrifuge under a positive pressure, thus eliminating the need for additional pumping machinery. When using the discharge devices described above, processors in the past have experienced some difficulty in the discharge thereby of viscous components. The tendency has been for the viscous components to firm up in the discharge passages of the skimming or paring device blocking further discharge and necessitating the disassambly of portions of the machine for cleaning. The problem of course may be met by selecting another type of discharge means. For instance, a simple ring darn may be used over which the discharge may spill to the outside of the bowl. With the new selection, however, the advantages of the skimming or paring device are absent and processors have not been satisfied with this alternative.

To avoid clogging of skimming devices in the prior art, the viscous component has been diluted in the bowl. Disclosing such dilution is the US. Patent 2,261,394 which issued Nov. 4, 1941. The earlier devices, however, provided for the use of the thinning liquid in the centrifuge zone itself and as a result led to disturbance of the centrifuged liquids to thereby hamper the efiiciency of the operation. Further, earlier devices did not provide for the use of a thinning liquid in a machine which was of the overhead or suspended type.

The present invention is concerned with the separation of the viscous component by skimming techniques and at the same time assures that there will be no blocking or clogging of the discharge passages of the skimming device.

Other objects of the invention will be understood with further reference to the following specification and the attached drawing forming a part thereof and in which:

FIGURE 1 is a sectional view of the upper portion of a centrifuge embodying the invention; and

FIGURE 2 is an enlarged sectional view taken on the line 2--2 of FIGURE 1.

Briefly, then, the invention relates to the discharge of I a viscous component by skimming techniques. More specifically the centrifuge involved may provide for the projection of a diluting liquid down alongthe'centrifuge ICC shaft to a vaned target which projects the liquid out into the viscous component skimmer pocket.

Referring more specifically to the drawings, FIGURE 1 is a fragmentary sectional view of a centrifuge embodying the invention and generally designated 10. It comprises a bowl 12 mounted for rotation by a suspending and driving shaft 14. The bowl structure may include a set 16 of frusto-conical discs (only two of which are shown) which are disposed about a vaned center tube 16:: and operate in the conventional manner to increase the efficiency of the separation. The feed liquid is delivered to the lower end of the centrifuge by feed means (not shown).

Mounted on the top of the bowl 12 is the heavy phase discharge housing 18 and the light phase discharge h'ousing 20. The housing 20 is supported on the dividing cone 22 secured between the upper end of the center tube 16a and the bowl top. In between the dividing cone 22 and housing 18 are a plurality of spaced ribs 24 which space the elements properly and permit passage of the heavy liquid from the centrifuge bowl into a pocket 26 facing inwardly and formed between the housings 18 and 20. The ribs widen in the pocket 26 and comprise part of radial vanes 28 which assure rotation of the liquid within the pocket 26 with the bowl.

The housing 20 together with the inward annular wall 30 also supported on the dividing cone 22 forms a pocket 32 which is provided with vanes 34. In operation separated light liquid from the centrifuge bowl spills over the annular wall 30 into the pocket 32. The wall 30 is formed with a plurality of radially inward extending vanes 30a.

Surrounding the drive and supporting shaft 14 is a stationary discharge assembly comprising the paring discs 36 and 38. The structure of the paring discs are comparable. As shown in FIGURE 1 the disc 36 is annular and provided with passages 37 which may be curved and extend from the periphery of the device to an inward discharge channel 40. The channel is formed between the tubular exterior wall 42 of the paring device 36 and the tubular wall 44 of the lower paring device 38. Spacing ribs 46 are provided to hold the two tubular portions in proper relation.

The lower paring device 38 comprises a pair of spaced sideplates with bafiles in between. Discharge passages 48 extend inward from the periphery of the device to the inward discharge channel 50 between the tubular element 44 and the inner tubular element 52. Ribs 54 hold these two elements in proper relative position.

The paring device assemblies are supported as shown on the centrifuge cover which is stationary. The upper ends of the passages 40 and 50 communicate respectively with discharge conduits 56 and 58 as shown.

The opposite faces of the paring device 36 are provided with spaced annular ribs 60 and 62 in accordance with patent application Ser. No. 419,086, filed Dec. 17, 1964. These ri-bs which are disposed concentrically about the axis of the centrifuge serve to deflect outward and into the liquid of the pocket 26 liquid moved inward by the secondary flow phenomenon. It will be understood that the liquid level is such that some ribs are normally immersed in the liquid in the pocket 2-6.

Similarly ribs 60 and 62 are provided for the same purpose on the paring device 38.

A splash shield 63 is provided on the underface of the paring device 36 and also serves to control turbulence or splashing. Passages 65 through the paring disc 36 provide means for venting gas pressures which may develop on either side of the disc.

Mounted on stationary structure comprising the discharge conduits 56 and 58 is a supplemental liquid introducing nozzle 64. The nozzle has a large end adapted to receive a supply of supplemental liquid, for instance hot water, and a smaller nozzle end 64a which is perpendicular to the body portion of the structure and directs the liquid in a jet down the annular space between the shaft 14 and the tubular element 52.

Secured to the upper end of the center tube 16a is an annular supplemental liquid deflecting target 66. The target is threadedly received into the upper end of the center tube and bears on its upper surface a plurality of radially directed vanes 68. The inner surface of the target 66 is provided with a seal 70 which may be of elastomeric material ad snugly embraces shaft 14 to keep supplemental liquid from flowing downward on the shaft. It will be understood that there is no relative rotary motion between the target and the shaft 14; both rotate at the speed of the bowl.

The upper surface of the target and the vanes 68 being at the level of the pocket 32 direct the supplemental liquid thereinto in a fashion which because of the turbulence on contact thoroughly mixes and homogenizes the incoming supplemental liquid and the viscous component already in the pocket. This mixing serves to dilute the viscous component, reducing its viscosity and making it easier to discharge out of the passages of the paring device 38.

In operation the feed is delivered to the lower end of the centrifuge vby means not shown and the lighter discharge spills over the annular dam 30 and finds its way into compartment 32. Similarly the heavier liquid discharge moves through the passages 24 to the discharge pocket or chamber 26. The supplemental liquid is introduced through the nozzle 64, jets downwardly toward the target 68 and mixes with the viscous lighter discharge of the chamber 32. It will be understood that this not only makes the lighter discharge less viscous so that it flows more easily through the passages 50 and out the collector 58 but at the same time it avoids any contamination of the liquid in the centrifuging zone of the bowl with a diluting supplemental liquid.

An additional benefit from the apparatus embodying the invention is that the heated supplemental liquid can be used to preheat the passages through which the liquid will flow thereby reducing likelihood that the viscous liquid will plug and clog due to its own viscosity.

Another advantage of the structure disclosed is that because the feed rate of supplemental liquid can be controlled, just the right amount can be introduced to the pocket to dilute the viscous component sufficiently to avoid pluggage without overdiluting. Since the rate at which the viscous component will build up in the bowl will vary depending on its concentration and the main feed rate, this flexibility is extremely desirable.

The invention has been used successfully in the separation of a very viscous protein-fat phase from corn sugar solution. Previously the sticky lighter phase mud from the separation had clogged the skimming device and associated passages. Under the present invention the machine installed in a corn sugar plant freely discharged the viscous mud after it was diluted and reduced in viscosity by hot water through the nozzle 64.

It should be understood that variations from the disclosed structure may be employed without exceeding the scope of the present invention. For instance the invention may be used in the discharge of a machine having a horizontal as well as a vertical axis or in the discharge of a machine of an altogether different type, for instance, a worm machine. Further it is of course contemplated i that the invention may be used in a wide range of separations, the sugar operation being merely illustrative.

Therefore, it is to be understood that the above particular description is by way of illustration and not of limitation, and that changes, omissions, additions, substitutions, and/or other modifications may be made without departing from the spirit of the invention. Accordingly, it is intended that the patent shall cover, by suittable expression in the claims, the various features of patentable novelty that reside in the invention.

We claim:

1. A centrifuge for the separation of viscous component from a mixture with a liquid comprising A supported rigid drive spindle extending downwardly,

A centrifuge bowl having an axis and mounted on its axis on the lower end of the spindle,

Means for delivering feed to the bowl,

A-n inwardly facing annular pocket disposed on the bowl about the axis with passage means from the interior of the bowl to the pocket for the passage of the separated component,

A stationary skimming device mounted adjacent the bowl and extending outward into the pocket and adapted to skim said component from the pocket,

A stationary nozzle disposed above the bowl and adjacent the shaft and adapted to direct a supplemental liquid in a downward stream parallel to and adjacent the shaft, and

An annular deflector closely surrounding the shaft at the level of the pocket and mounted to rotate with the bowl, the annular deflector having radial vanes and adapted to accelerate the supplemental liquid outward into the pocket, whereby the viscous component is intimately contacted with and diluted with the supplemental liquid to facilitate discharge through the stationary skimming device.

2. A centrifuge for the separation of viscous component from a mixture with a liquid comprising A supported rigid drive spindle extending downwardly,

A centrifuge bowl having an axis and mounted on its axis on the lower end of the spindle,

A center tube mounted in the bowl about the spindle,

Means for delivering feed to the bowl,

An inwardly facing annular pocket disposed on the bowl about the axis with passage means from the interior of the bowl to the pocket for the passage of the separated component,

A stationary skimming device mounted adjacent the bowl and extending outward into the pocket and adapted to skim said component from the pocket,

A stationary nozzle disposed above the bowl and adjacent the shaft and adapted to direct a supplemental liquid in a downward stream parallel to and adjacent the shaft, and

An annular deflector secured to the upper end of the center tube and closely surrounding the shaft at the level of the pocket and mounted to rotate with the bowl, the annular deflector having radial vanes and adapted to accelerate the supplemental liquid outward into the pocket, whereby the viscous component is intimately contacted with and diluted with the supplemental liquid and reduced in viscosity to facilitate discharge through the stationary skimming device.

3. A centrifuge comprising a bowl mounted to rotate about an axis and having an annular discharge pocket for the discharge of a separated component, a stationary paring device disposed Within the pocket and adapted to remove separated component from the pocket, a nozzle mounted adjacent the bowl axis and adapted to direct a diluting liquid in a stream parallel to the axis, a deflecting means mounted on the bowl at the level of the discharge pocket and adapted to direct the stream out into the pocket, whereby a viscous separated component in the 5. pocket can be intimately contacted with and reduced in viscosity by such diluting liquid to facilitate discharge.

4. A centrifuge as described in claim 3 wherein the deflecting means is an annular target disposed about the axis and having radial vanes.

References Cited by the Examiner UNITED STATES PATENTS 2,302,168 11/1942 Ayres et a1. 2,412,099 12/1946 Sender M. CARY NELSON, Primary Examiner.

233--14 10 HENRY T. KLINKSEIK, Examiner. 

1. A CENTRIFUGE FOR THE SEPARATION OF VISCOUS COMPONENT FROM A MIXTURE WITH A LIQUID COMPRISING A SUPPORTED RIGID DRIVE SPINDLE EXTENDING DOWNWARDLY, A CENTRIFUGE BOWL HAVING AN AXIS AND MOUNTED ON ITS AXIS ON THE LOWER END OF THE SPINDLE, MEANS FOR DELIVERING FEED TO THE BOWL, AN INWARDLY FACING ANNULAR POCKET DISPOSED ON THE BOWL ABOUT THE AXIS WITH PASSAGE MEANS FROM THE INTERIOR OF THE BOWL TO THE POCKET FOR THE PASSAGE OF THE SEPARATED COMPONENT, A STATIONARY SKIMMING DEVICE MOUNTED ADJACENT THE BOWL AND EXTENDING OUTWARD INTO THE POCKET AND ADAPTED TO SKIM SAID COMPONENT FROM THE POCKET, A STATIONARY NOZZLE DISPOSED ABOVE THE BOWL AND ADJACENT THE SHAFT AND ADAPTED TO DIRECT A SUPPLEMENTAL LIQUID IN A DOWNWARD STREAM PARALLEL TO AND ADJACENT THE SHAFT, AND AN ANNULAR DEFLECTOR CLOSELY SURROUNDING THE SHAFT AT THE LEVEL OF THE POCKET AND MOUNTED TO ROTATE WITH THE BOWL, THE ANNULAR DEFLECTOR HAVING RADIAL VANES AND ADAPTED TO ACCELERATE THE SUPPLEMENTAL LIQUID OUTWARD INTO THE POCKET, WHEREBY THE VISCOUS COMPONENT IS INTIMATELY CONTACTED WITH AND DILUTED WITH THE SUPPLEMENTAL LIQUID TO FACILITATE DISCHARGE THROUGH THE STATIONARY SKIMMING DEVICE. 